a) √20449 + √285156 - √54289 = √143² + √534² - √233² = 143 + 534 - 233 = 444
b) √2916 + √41616 - √11664 = √54² + √204² - √108² = 54 + 204 - 108 = 150
c) √229441 + √301401 - √546121 = √479² + √549² - √739² = 479 + 549 - 739 = 289
d) √467856 + √264196 - √826281 = √684² + √514² - √909² = 684 + 514 - 909 = 289
